Shards Online is aiming to provide. A recent interview with the developers discusses the idea, with studio co-founder Derek Brinkmann explaining that it's one of the first steps to dismantling the idea that the designers have to tell you how to enjoy yourself.
Citadel Studios is a team made up of former Ultima Online developers who wondered why more games haven't embraced the idea of taking live events to their logical conclusion with modern technology. Shards Online is set in a multiverse, with several different worlds featuring slightly different rules, while players can tweak the overall structure to their individual preferences by running their own servers. The game is in development for Windows, Linux, and Mac, with an alpha expected later this year.